Dennis has 8 baseball cards with him right now. this makes up 15% of the total in his collection. how many baseball cards does dennis have in total in his collection?

The first week samantha learned to read braille, she could read 10 words per minute. in the second week she increased her speed by 20%. in the third week she increased her speed again by another 25%. how many words could she read per minute by the third week? hurry and tell me!